Wednesday, January 16, 2019

Speaker "Kits" Arrived Today

And calling these things "kits" is being overly generous.

Calling them "semi-kits" would be more accurate, but even that's a stretch.

Nope, this is a collection of parts, packed in a box, and shipped out.

And why, pray tell, are power tools and hole saws on the bench with right out-of-the-box speaker "kits"?

Why because they didn't give you any way to connect the assembled speaker to the stereo! I suppose I could have drilled a small hole, and run a few feet of wire out, but what then? No, you need an Interface Connector to handle that function. Since the output connectors on most real stereos are some form of a "5-Way" Binding Post that accepts banana plugs, having matching connectors on the speaker is the way to go. So, drill a 2" hole with the hole saw, and mount these nice little "5-Way" Binding Posts plates in the new holes.

Screws not included, of course.

After drilling, just press-fit in the hole.


Might as well do both at once while I have the tools out.....

The pre-made hole in the back panel of the speaker is for the "Tuned Port", a deliberately sized "air leak" in the box that lowers it's Resonant Frequency, which increases the lower (Bass) frequencies the speaker can reproduce.


Mocking them up sans glue.....

And here they are with the side panels and stiffening baffle glued in and lightly clamped.

I'm not a cabinet maker, and never pretended to be one, so I have to say these 3/4" thick, MDF, "CNC Cut" pieces fit together beautifully! After a 24-hour glue curing time, I'll fit the two remaining pieces, and glue them in. The front doesn't get glued on until the very last, and I'm thinking of maybe screwing it on with a thin gasket in there.

The enclosures get lined with acoustic foam to subdue high frequencies inside the box (makes the treble less "harsh"), and the cross-over assemblies have to be built.

No circuit board provided, of course.

Then the speakers get screwed into the front panel with the screws that were not included with the "kit", and the two speakers get wired to the cross-over network, and the input to the cross-over network gets wired to the nifty little Interface Connector I installed on the back, guess who supplies the wire, and the front gets mounted (somehow), and they should be ready to play.

Rather than leave these naked MDF, I'm going to coat them with something like bed liner that Parts Express sells. It's water-based, so the odor won't drive you out while it's curing, and it's extremely durable. I'll sand them out before I do it, and come up with some way to make the front removable.

Oh, and I've had to order about $50 in additional parts (so far) to build my "kit" speakers.


  1. Over-the-counter speakers from Amazon look more and more attractive, although yours will likely sound better.

    1. Oh, I could pretty these up with stain and a nice urethane finish, but since they won't be in the living room, and subject to Wife Approval, they'll get painted Industrial Black.

  2. Are these for a sound system? What are the specs for the low end frequency response? Will probably last forever. I had a buddy that built a clock radio from Heathkit back in the eighties...he still uses it. You're really quite handy.

    1. Yep, these are for the Heathkit AR-15 Stereo Receiver I'm rebuilding.

      The woofer is a 7", aluminum cone unit, and mounted in the enclosure, they go down to 45 Hz. The high end is supposed to be 20kHz, probably far beyond what I can hear these days!

    2. Most of us can't hear anywhere near 20k hertz. I love a good speaker system. It seems all I have now are 5.1 but I think I prefer a two-way pair with a good amp.

    3. The last time my hearing was properly tested (sat in a booth with headphones on) I think it rolled off pretty substantially above 16kHz.

  3. I should have looked at this when you posted it. When I saw the title, I thought speakers for a boatanchor radio.

    To quote Emily Litella, "that's very different. Never mind".

    1. These might work for that, but they're not made for low power (1~2 Watts) like a BA would put out.

  4. 40 years ago, when I was in the Air Force and hadn't gone oversea to buy a stereo yet, I went to radio shack and bought a pair of three way coaxial speakers.
    Bought some chip board and made huge cabinets to mount them in.
    Bass reflex with a tunable port (a variable opening slot).
    Lined with fiberglass insulation.
    Driven by a 4 watt (8 peak!) turntable, eightrack, FM tuner combo.
    Super efficient and frankly my later Boses didn't sound any better.
    I used those cabinets as packing cases later.

    1. I never built a set of speakers before except maybe a 6x9 in a box.

    2. Well, your kits certainly look more sophisticated.
      The reason my boxes worked so well was they were so big. :)

  5. Ah yes, 'some' assembly required...

    1. Yes, and the assembly requires parts not provided.

      That's the annoying part.

      Don't get me started on the "instructions" they provided.....


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